Briefly About Secure Sockets Layers (SSL)

What is Secure Sockets Layers (SSL)?

Secure Sockets Layer (SSL) is the most widely used technology for providing a secure communication between the web client and the web server. Most of us are familiar with many sites such as Gmail, Yahoo etc. using https protocol in their login pages. When we see this, we may wonder what’s the difference between http and https. In simple words HTTP protocol is used for standard communication between the Web server and the client. HTTPS is used for a SECURE communication.

What exactly is Secure Communication?
Suppose there exists two communication parties A (client) and B (server).
Working of HTTP
When A sends a message to B, the message is sent as a plain text in an unencrypted manner. This is acceptable in normal situations where the messages exchanged are not confidential. But imagine a situation where A sends a PASSWORD to B. In this case, the password is also sent as a plain text. This has a serious security problem because, if an intruder (hacker) can gain unauthorized access to the ongoing communication between A and B, he can see the PASSWORDS since they remain unencrypted. This scenario is illustrated using the following figure.
Now let’s see the working of HTTPS
When A sends a PASSWORD (say "mypass") to B, the message is sent in an encrypted format. The encrypted message is decrypted on B’s side. So even if the Hacker gains an unauthorized access to the ongoing communication between A and B he gets only the encrypted password ("xz54p6kd") and not the original password. This is shown below.
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How is HTTPS implemented?
HTTPS is implemented using Secure Sockets Layer (SSL). A website can implement HTTPS by purchasing an SSL Certificate. Secure Sockets Layer (SSL) technology protects a Web site and makes it easy for the Web site visitors to trust it. It has the following uses
1. An SSL Certificate enables encryption of sensitive information during online transactions.
2. Each SSL Certificate contains unique, authenticated information about the certificate owner.
3. A Certificate Authority verifies the identity of the certificate owner when it is issued.

How Encryption Works?
Each SSL Certificate consists of a Public key and a Private Key. The public key is used to encrypt the information and the private key is used to decrypt it. When your browser connects to a secure domain, the server sends a Public key to the browser to perform the encryption. The public key is made available to every one but the private key (used for decryption) is kept secret. So during a secure communication, the browser encrypts the message using the public key and sends it to the server. The message is decrypted on the server side using the Private Key (Secret key).
How to identify a Secure Connection?
In Internet Explorer, you will see a lock icon in the Security Status bar. The Security Status bar is located on the right side of the Address bar. You can click the lock to view the identity of the website.
In high-security browsers, the authenticated organization name is prominently displayed and the address bar turns
GREEN when an Extended Validation SSL Certificate is detected. If the information does not match or the certificate has expired, the browser displays an error message or warning and the status bar may turn RED.
So the bottom line is, whenever you perform an on-line transaction such as Credit card payment, Bank login or Email login always ensure that you have a secure communication. A secure communication is a must in these situations. Otherwise there are chances of
Phishing using a Fake login Page.

How secure is the encryption used by SSL?
It would take significantly longer than the age of the universe to crack a 128-bit key.
SSL uses public-key encryption to exchange a session key between the client and server; this session key is used to encrypt the http transaction (both request and response). Each transaction uses a different session key so that even if someone did manage to decrypt a transaction, that would not mean that they would have found the server's secret key; if they wanted to decrypt another transaction, they'd need to spend as much time and effort on the second transaction as they did on the first. Of course, they would have first have to have figured out some method of intercepting the transaction data in the first place, which is in itself extremely difficult. It would be significantly easier to tap your phone, or to intercept your mail to acquire your credit card number than to somehow intercept and decode Internet Data. Servers and browsers do encryption ranging from a 40-bit secret key to a 128-bit secret key, that is to say '2 to the 40th power' or '2 to the 128th power'. Many people have heard that 40-bit is insecure and that you need 128-bit to keep your credit card info safe. They feel that using a 40-bit key is insecure because it's vulnerable to a "brute force" attack (basically trying each of the 2^40 possible keys until you find the one that decrypts the message). This was in fact demonstrated when a French researcher used a network of fast workstations to crack a 40-bit encrypted message in a little over a week. Of course, even this 'vulnerability' is not really applicable to applications like an online credit card transaction, since the transaction is completed in a few moments. If a network of fast computers takes a week to crack a 40-bit key, you'd be completed your transaction and long gone before the hacker even got started.
Of course, using a 128-bit key eliminates any problem at all because there are 2^128 instead of 2^40 possible keys. Using the same method (a networked of fast workstations) to crack a message encrypted with such a key would take significantly longer than the age of the universe using conventional technology. Remember that 128-bit is not just 'three times' as powerful as 40-bit encryption. 2^128 is 'two times two, times two, times two...' with 128 two's. That is two, doubled on itself 128 times. 2^40 is already a HUGE number, about a trillion (that's a million, million!). Therefore 2^128 is that number (a trillion), doubled over and over on itself another 88 times. Again, it would take significantly longer than the age of the universe to crack a 128-bit key.

Key Size Possible Key Combinations
2-bit       2^2 2x2                             = 4
3-bit       2^3 2x2x2                         = 8
4-bit       2^4 2x2x2x2                     = 16
5-bit       2^5 2x2x2x2x2                 = 32
6-bit       2^6 2x2x2x2x2x2             = 64
7-bit       2^7 2x2x2x2x2x2x2         = 128
8-bit       2^8 2x2x2x2x2x2x2x2     = 256
9-bit       2^9 2x2x2x2x2x2x2x2x2             = 512
10-bit    2^10 2x2x2x2x2x2x2x2x2x2        = 1024
11-bit    2^11 2x2x2x2x2x2x2x2x2x2...     = 2048
12-bit    2^12 2x2x2x2x2x2x2x2x2x2...     = 4096
16-bit    2^16 2x2x2x2x2x2x2x2x2x2...     = 65536
24-bit    2^24 2x2x2x2x2x2x2x2x2x2...     = 16.7 million
30-bit    2^30 2x2x2x2x2x2x2x2x2x2...     = 1 billion (1,073,741,800)

40-bit    2^40 2x2x2x2x2x2x2x2x2x2...     = 1 trillion (1,097,728,000,000)
56-bit    2^56 2x2x2x2x2x2x2x2x2x2....    = 72 thousand quadrillion (71,892,000,000,000,000)
128-bit  2^1282 multiplied by 2128 times over. = 339,000,000,000,000,000,000,000,000,000,000,000
(give or take a couple trillion...)
Doing the math, you can see that using the same method that was used to break 40-bit encryption in a week, it would take about 72 million weeks (about 1.4 million years) to even break '56-bit medium' encryption and significantly longer than the age of the universe to crack a 128-bit key. Of course the argument is that computers will keep getting faster, about doubling in power every 18 months. That is true, but even when computers are a million times faster than they are now (about 20 years from now if they double in speed every year), it would then still take about 6 thousand, trillion years, which is about a million times longer than the Earth has been around. Plus, simply upgrading to 129-bit encryption would take twice as long, and 130-bit would take twice as long again. As you can see, it's far easier for the encryption to keep well ahead of the technology in this case. Simply put, 128-bit encryption is totally secure.

How do I know if encryption is enabled or not?
Your Browser (Netscape or Internet Explorer) will tell you.
In Netscape versions 3.X and earlier you can tell what kind of encryption is in use for a particular document by looking at the "document" information" screen accessible from the file menu. The little key in the lower left-hand corner of the Netscape window also indicates this information. A solid key with three teeth means 128-bit encryption, a solid key with two teeth means 40-bit encryption, and a broken key means no encryption. Even if your browser supports 128-bit encryption, it may use 40-bit encryption when talking to other servers or to servers outside the U.S. and Canada. In Netscape versions 4.X and higher, click on the "Security" button to determine whether the current page is encrypted, and, if so, what level of encryption is in use. In Microsoft Internet Explorer, a solid padlock will appear on the bottom right of the screen when encryption is in use. To determine whether 40-bit or 128-bit encryption is in effect, open the document information page using File->Properties. This will indicate whether "weak" or "strong" encryption is in use.

What about warnings or errors about the Secure Certificate?
Your personal Security settings will determine what warnings you see.
Depending on how your security settings are setup in your Browser, you may also see information about our Certificate when you enter the secure directories. This information will usually include the Dates that the Certificate is valid for, the site name that the Certificate has been issued to, and the Certificate Authority (or 'CA') that issued the Certificate. You can also usually view the Certificate to see information about the various parties, including Inet2000 and our CA.
The most common warning is that you have not previously chosen to Trust the authority. This is a normal warning if you haven't already purchased anything online from a Merchant who's certificate was issued by a Certificate Authority that you haven't told your browser to trust from now on. Of course, you may well have no errors, warnings or information screens at all - again, largely depending on the way you've got your security settings set in your Browser. In any case, the encryption level and the security is the same whether you've got your settings low (don't warn me about anything) or very high (warn and inform me about everything). Either way, your data is still encrypted and still secure.

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